Similar levels of cell death were seen in all 20S proteasome inhibitor cases, indi cating that increased survival was not responsible for the higher numbers of cells observed with the adenocar cinoma cell lines. Together, these results establish that OE33 adenocar cinoma cells exhibit a higher invasive potential and growth rate than the non tumourigenic Het1A cells. PEA3 is required for the increased invasion and proliferation in OE33 cells PEA3 has been established as an important regulator of cell invasion in colon cancer and gastric adenocarci noma cells through regulation of MMP 1 and MMP 7 respectively. We therefore wanted to investigate if PEA3 is also a regulator of oesophageal cancer cell invasion. A siRNA mediated PEA3 knockdown strategy was employed to reduce PEA3 expression.

Matrigel invasion chambers were again utilised to assess in vitro invasion. Het1A cells do not express PEA3 at high levels making them a valid control for PEA3 depletion. Indeed, depletion of PEA3 did not alter Het1A cell invasion when compared to cells treated with control duplexes. This indicates that the PEA3 SMARTpool is unlikely to have an off target effect on cell invasion. Inhibitors,Modulators,Libraries In contrast, PEA3 depletion reduced the invasive cap abilities of OE33 by nearly 60%, indicating that PEA3 is important for invasion by OE33 cells. To further extend our link between PEA3, MMP 1 and invasion, we asked whether MMP 1 depletion in OE33 cells would also lead to a decrease in invasion. This was indeed the case, albeit to a lesser extent, suggesting that PEA3 likely drives invasion through multiple targets in addition to MMP 1.

Research on PEA3 has mainly focused on its ability to regulate MMPs and cell invasion. A previous studies in breast and ovarian cancer cells demonstrated that PEA3 controls the expression of cell cycle regulators such as Cyclin D3 and p21 respectively, and hence sug gested that it might be involved in Inhibitors,Modulators,Libraries controlling prolifera tion. We therefore investigated if PEA3 was important for oesophageal cancer cell proliferation. First we depleted PEA3 in Het1A cells. Over a 96 hour period, the proliferation of Het1A cells was similar to cells trea ted with control duplexes. In contrast, OE33 cells treated with either SMARTpool siRNA against PEA3 or the deconvoluted siRNA constructs A and B, exhibited a sustained a growth arrest. In summary, PEA3 is required for the proliferation and enhanced invasive properties of OE33 adenocarci noma cells.

ERK MAP kinase signalling is important for OE33 cell proliferation and invasion Previous studies have demonstrated that PEA3 activity is potentiated by ERK MAP kinase pathway signalling and that this signalling Inhibitors,Modulators,Libraries pathway plays an important role in cancer cell properties, Inhibitors,Modulators,Libraries Inhibitors,Modulators,Libraries including invasion and prolif eration. selleck chem We therefore investigated the activation status of this pathway in oesophageal derived cell lines by western analysis using an anti phospho ERK anti body.